The present disclosure relates in general to drilling rigs, and in particular to a drilling rig having vertically-spaced dual racking boards.
Drilling operations often require intermittent removal of a drill string from a wellbore in a process sometimes referred to as “tripping out”. This occurs, for example, when it is desirable to introduce casing into the wellbore. During this time, rotation of the drill string and circulation of drilling fluids are typically suspended. The drill string is then lifted by lifting equipment attached to a mast located above the wellbore and broken down into stands of pipe. As the stands of pipe are removed from the drill string, each is accommodated within a racking board that is attached to the mast. Generally, sections of casing or liner are not stored vertically in racks that are attached to the mast, but in a horizontal position at a location remote from the drill floor. Thus, each time a section of casing is needed, the section of casing is moved from the location remote from the drill floor, brought from the horizontal position to a vertical position, and then stabbed into the previous casing section that had been inserted into the well. As drilling operations are suspended during casing operations, the time required to move each casing section into position delays drilling operations. The present disclosure is directed to a dual racking board drilling rig and methods that overcome one or more of the shortcomings in the prior art.